By MIKE PESOLI

ARLINGTON, Va. (AP) — For the last two years, Army Sgt. 1st Class Andrew Jay has been dutifully guarding the Tomb of the Unknown Soldier at Arlington National Cemetery.

Rain or shine, snow or sleet, for 24 hours a day, 365 days a year, Jay and the other guards on watch duty serve as both protectors and commemorators of a national tribute to America’s unidentified and missing service members.

With Jay’s final walk scheduled for June 2, this Memorial Day will hold special significance for him as the cemetery prepares for a string of events honoring those who paid the ultimate price for their country.

“It’s meant a lot,” Jay, 38, told The Associated Press. “I’m going to try to make sure it doesn’t define me, but it was definitely a defining moment in my career.”

The Associated Press was given rare access to the changing of the guard at the sunrise hour, as the cemetery was still closed to the public.

Jay, who is from Indianapolis, volunteered for the position after serving in the Kentucky-based 101st Airborne Division, which specializes in air assault operations and is known for its record in World War II. He trained for almost 18 months for the guard duty.

“The training is unlike anything I’ve ever done in my career so far,” he said. “It’s more than the physical aspect of any other Army school you might think of.”

The guards, also known as sentinels for their watchful duty, train even on their off-days, walking on the mat for two hours straight to build up muscular endurance.

But that isn’t the only endurance required of the sentinels.

“It’s a lot of mental ability,” Jay said. “You have to be locked in for a nine-minute guard change, but then also your 30-minute walk. So, what you’re thinking about kind of varies between soldier to soldier.”

The sentinels spend half an hour walking the mat in the warmer months and an hour during colder months. They perform a dramatic changing of the guard at the grave site that visitors to the Washington area flock to see, marching 21 steps down the mat, turning and facing east for 21 seconds, then north for 21 seconds and then back down the mat for 21 more, repeating the process.

The number refers to the high military honor of the 21-gun salute, which can be heard booming throughout the cemetery and surrounding areas during military funerals on the grounds.

There are currently three unidentified U.S. service members buried in the tomb: one from World War I, one from World War II and one from the Korean War.

With Memorial Day approaching, the cemetery — which is run by the U.S. Army and has 3 to 4 million visitors annually — will hold a number of events to honor fallen service members. Just before Memorial Day weekend, the 3rd U.S. Infantry Regiment places American flags at the grave sites of more than 260,000 service members buried at the cemetery — an event known as “Flags In.” On the Sunday of Memorial Day weekend, the public is invited to leave flowers at the Tomb of the Unknown Soldier for Flowers of Remembrance Day.

“Memorial Day still retains the purpose that it had back in 1868 during that first official observance here in Arlington,” said Allison Finkelstein, the senior historian of Arlington National Cemetery. “It is the day to remember and honor our war dead.”

There have been 733 tomb guards since 1958. On average, seven to nine tomb guards work every day.

“The honor of guarding them isn’t just about the Three Unknowns, it’s about everybody that lays here in the cemetery and what they gave in the pursuit of freedom,” Jay said.